Presentation by Karl-Søren Geertsen (Danish Coastal Authority, Denmark), at the Delft3D User Days, during Delft Software Days - Edition 2022. Wednesday, 16 November 2022.

1. Danish Floods Directive
using SFINCS
by the Danish Coastal Authority
Delft Software Days 2022
Karl-Søren Geertsen
Coastal engineer - MScEng
16 November 2022

2. Agenda
• National flood obligations in DCA
• Why do we need a model-tool as SFINCS in DCA?
• Verification of SFINCS in Denmark – Historical event
• Future applications of SFINCS in DCA
/ Coastal Authority / Application of SFINCS in Denmark
2

3. National flood obligations in DCA
• The EU Floods Directive (6 years frame work)
• National flood risk assessment to identify areas of potential significant flood risk
• Flood hazard and risk mapping in high risk areas
• National climate adaptation
• Municipalities has become authority of coastal protection in DK!
• Support municipalities with data and development of new tools for flood risk management
• National extreme water level analysis (5 years frame work)
/ Coastal Authority / Application of SFINCS in Denmark
3

4. Why do we need a model-tool as SFINCS in DCA?
• DCA flood modelling has previously been based on two model approaches
• Asked to investigate alternative model approaches
- National risk assessment
- Detailed flood modelling
• Found the SFINCS introduction article
/ Coastal Authority / Application of SFINCS in Denmark
4
Computational demand
Accuracy
Full physics
dynamic
Bathtub
steady state
?

5. Why do we need a model-tool as SFINCS in DCA?
SFINCS model ”Havvand på land” – bathtub model
/ Coastal Authority / Application of SFINCS in Denmark
5
Low computational time ~ minutes
(Only sea)
Approx. No Computational
time
• The Southern part of the Island
Lolland is appointed as a risk area
under the Floods Directive.
• For this, we previously had used full
physic models for detailed
modelling.
• With SFINCS the model can
compute the flooding around 30
minutes and the results are
comparable.

6. Verification of SFINCS in Denmark – Historical event
/ Coastal Authority / Application of SFINCS in Denmark
6
• November 2006
storm surge
• Intense northerly
winds.
• Severe flooding in
the inner Danish
waters

7. Verification of SFINCS in Denmark – Historical event
Model resolution 25x25m + subgrid (5x5m) 11 hours - on local pc!
Model resolution 50x50m + subgrid (5x5m) 1,5 hours - on local pc!
Model resolution 100x100m + subgrid (5x5m) 16 min - on local pc!
/ Coastal Authority / Application of SFINCS in Denmark
7

8. Odensefjord – Stigevej
Local municipality input:
Municipality of Odense:
Peak wl 184cm
Flood depth 25cm
/ Coastal Authority / Application of SFINCS in Denmark
8

9. Nyborg Havn
Local municipality input:
Municipality of Nyborg:
Peak wl 225cm
Flood depth 50cm
/ Coastal Authority / Application of SFINCS in Denmark
9

10. Lohals – Smedegade
Local municipality input:
Municipality of Langeland:
Peak wl 200cm
Flood depth 60cm
Ref: Langelands kommune
/ Coastal Authority / Application of SFINCS in Denmark
10 Ref: Langelands kommune

11. Future applications of SFINCS in DCA
• The EU Floods Directive
• SFINCS will be implemented as a screening tool to identify areas of high flood risk in 2023
• Flood hazard and risk mapping of appointed potential flood risk areas will be conducted
utilizing SFINCS in 2024-2025
/ Coastal Authority / Application of SFINCS in Denmark
11
Source Pathway Receptor

12. / Coastal Authority / Application of SFINCS in Denmark
12
Flood risk tool
Output:
Flood risk maps
Engine = SFINCS:
National scale
Efficiency
Accuracy
Local scale
Accuracy
Efficiency
National climate adaptation tool
• The tool is
intended to
support
municipalities in
managing the flood
risk (national scale)
• Support
municipalities in
working together
with consultancies
(local scale)
• Deeply inspired by
the development of
CFRSS work in
USA
2. Local scale
Similar to CFRSS
1. National scale
Screening

13. National operational dike-flood model
• Dike safety assessment will be conducted from 2023-2026
• Is it possible to couple SFINCS with a dike safety assessment model?
• Determine potential flooding in case of dike failure.
/ Coastal Authority / Application of SFINCS in Denmark
13

14. / Coastal Authority / Application of SFINCS in Denmark
14